Bacterial sporulation represents an ideal system for studying the differential control of gene expression during a simple cell differentiation process. The possibilities for control of bacterial development by alterations in ribosomal structure will be investigated in Bacillus subtilis. A variety of single-site ribosomal mutants which cause sporulation, but not vegetative growth, to become temperature sensitive will be studied by genetic and biochemical techniques. It is hoped the results of this project will further our understanding of the mechanisms which control normal and abnormal cell development. In addition, this project should be of relevance to understanding the possibilities for sub-cellular defects which could result in neoplastic growth.